Surgical management of solitary nerve sheath tumors originating around the epiconus or conus medullaris: a retrospective case analysis based on neurological function

The objective of this retrospective case analysis was to evaluate the surgical impact on neurological functional recovery in cases of solitary spinal nerve sheath tumors (NSTs) originating around the epiconus, conus medullaris, or cauda equina and not associated with neurofibromatosis. This 10-year surgical study included 30 cases of spinal NSTs originating around the spine level of T12-L1 (epiconus-to-conus medullaris: Epi-CM group), and 15 cases of spinal NSTs originating below the spine level of L2 (cauda equina: CE group). A minimally invasive posterior unilateral approach was applied in 22 of 30 subjects in the Epi-CM group and in 14 of 15 subjects in the CE group. Total removal of the tumor was achieved in all cases except in two cases of subpial growth and foraminal extension in the Epi-CM group at the initial surgery. Functional assessment revealed satisfactory or acceptable neurological recovery in both groups. Twelve of 30 patients (40%) in the Epi-CM group demonstrated significant motor weakness of the ipsilateral leg, predominantly manifested as drop foot before surgery, and only 4 of 12 patients demonstrated complete recovery. Ten of 30 patients (33%) in the Epi-CM group demonstrated a significant disturbance of urination before surgery, and only 6 of 10 demonstrated complete recovery. No patients in the CE group demonstrated unsatisfactory recovery of leg motor weakness or urinary disturbance. The present study suggests that surgeons should be aware that spinal NSTs originating around the epiconus or conus medullaris may result in delayed or inadequate functional recovery, even after successful surgical resection of tumors.